Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Friday, June 03, 2011

A fat grub, and a pretty, strange fly are partners

This is a long story, so I will try to keep it simple.

Kirsten and I were out at Meryla Pass road, just taking in the sights, out towards Bundanoon Creek. We stopped off at the first creek crossing there (a deep gully) which plunges even further down towards the Bundanoon Creek Reservoir.

This first creek crossing is a nice dry rocky outcrop, which is very good for Orchids in most seasons, except just now. We found lots of leaves and seed pods, though.

As we got back to the car, to go down to Griffins Fire Trail and to admire the views along that road, back towards Red Hills Ridge and Fitzroy Falls, we noticed some strange insects flying around, with prominent white tail tufts. Most unusual, and looking for all the world like the kind of "flies" that Fly Fishermen spend their lives "tying".
We went for a drive further out to Griffin's Fire Trail, which I thoroughly recommend, even if you do not run all the way down to the Shoalhaven River, which my friend Tegyn likes to regard as a "training run". I prefer to admire the view from the top.

Flying "bristle-tailed insect" as I dubbed it in my filing system.

 What a handsome Insect (even from the underneath side)
At least you get to see the tail bristles, and his "equipment".
Click to enlarge the image.
While I was chasing these shots,
my friend Kirsten had discovered some totally different strange grubs.
"Come and have a look at these weird things" was how I remember her call to me. 

Female of Bird of Paradise Fly (Calipappus sp)
They are not agile, but grip strongly on the bark of Scribbly Gums. 

 Here is a colony of them hiding under the loose bark of the Scribbly Gum.

Here is one photographed on my 62mm lens cap.
Partly for scale (size) reference, and frankly I wanted to check
if they could bite me, sting me or otherwise inflict injury to me.
Seemingly not.
The antennae. There is a tiny dot behind the base of the antennae
Apparently it is the eye.
 There is no mouth or chewing parts, or sucking probe.
How do they eat?
This one is demonstrating some flexibility, righting itself.
On a 62 mm lens cap, it is obviously approx 45 mm long. Quite large.
This last shot is a bit blurry, but it reveals the soft powdery coating that some of these insects had.
It also reveals that the insect is very front-end oriented. Behind the last pair of legs, it has no obvious vital organs. What's that about?

Anyway, having searched all the obvious insect reference sites looking for what I assumed were "ephemeral" insects, without any luck, I sought expert help from Dave Rentz of Bunyipco

What a guy!

He quickly responded with the advice that my insects were very interesting (very large specimens) and that they were a kind of bug, related to the "scale insects". (That's a puzzle for me, as they had no "sucking probe" as you can see in the underneath head shot).

More importantly, he told me that my "two insects" were male and female of the same species!!!
Final clue - the males are called "Bird of Paradise flies". What a wonderful poetic name, (except they aren't true flies).

Wow, that's some sexual dimorphism.

Finally, Dave sent my email on to Dr Penny Gullan, Emeritus Professor in the School of Biology at the ANU.

Her reply is as follows:
  • Well what an amazing coincidence!  I was looking at my microscope slide-mounts of these insects today as I am training a colleague in identification of scale insects (Hemiptera: Coccoidea). Denis' photos are of the adult male (winged "fly"), called a bird-of-paradise fly, and his adult female (the large larviform insect) of the genus Callipappus (family Callipappidae, previously in Margarodidae which has been split into more than 10 families). Callipappus nymphs feed underground on the roots of their host plant (we know very little about which plants they feed on) and emerge from the soil as adults to mate. The female then pulls her abdomen into her thorax to make a chamber, or marsupium, into which she lays her eggs. Probably the double orifice behind the legs is where the cuticle invaginates for attachments of muscles that help to pull the abdomen into the thorax. When the eggs hatch the little nymphs, called crawlers, head back down into the soil. Autumn is the only time of year when the adults are around.  
Penny sent me a pdf copy of an article she has written about them. Unfortunately, I seem to be unable to upload to from the borrowed computer I am using at present. The article is called "Giant females and "Bird of Paradise Flies".

Of course, as often happens with the Internet, once you know the name, you can find lots of images.
Sure enough the Chew Family website on Insects of Brisbane has a page on them, which shows males and females "together" as proof positive of their relationship.

Many thanks to Dave, and it is a tribute to the power of the Blogging network that I was able to seek help and get this one sorted. Much appreciated, Dave.

I am off to meet Penny tomorrow, to take a few live, hopefully fertilized specimens to her, so she can try to get some more life-cycle data from them and their "crawlers" if any hatch.

Finally, Penny answered my last question, this afternoon, about why they had no "sucking mouth parts", if they are "bugs"?

Simple, they feed underground (on roots) in the larval or nymph stage, and then these emerge as mature females, whose only function is to mate, and then tuck their long bellies back inside themselves, to form the "marsupium", and hold the eggs until the "crawlers" hatch out.
No feeding = no need for mouth parts.
Devoted mothers, they live only to breed, and die.

A few last questions remain unanswered, for me.
  • If the females are virtually sightless, why are the males so spectacularly showy?
  • What's the advantage of the long bristle-tail? That shuttlecock tail appendage surely slows them down when flying.
  • What's the point in being such an attractive violet colour?


Snail said...

Excellent post, Denis. I've learnt a lot!

Penny will probably answer all your Qs tomorrow, but I'm wondering whether the males are showy for each other. Not all sexual dimorphism is driven by female choice. In many species (stag beetles, for example), males compete directly with each other for mates, sometimes with a bit of biffo, but often with a bit of judicious posturing. Maybe the bristle tail is something to do with that?

Also (and I'm just making this up as I type, you understand) the colour may not necessarily be for show. It might look quite different to other animals. Many birds, for instance, can see UV, so that attractive purple could be something else for them.

Gaye said...

Hello Denis,

fascinating finds, indeed. And it just goes to show what valuable observations we amateur naturalists can make, and contribute to science. Well done.

Your questions are very appropriate, and I'll be very interested in answers if they are forthcoming at any time.


Mark Young said...

Fascinating stuff! Who would've thought that those 2 were related! The male fly reminded me of the lures that fisherman use for fly fishing.

Denis Wilson said...

Thanks Gaye and Bronwyn.
It has been a very satisfying Blogging experience and something which reminds me of how much value there is in learning.
I should put that in Capitals - LEARNIMG.
I firmly believe knowledge ought be shared as widely as possible.
It turns out Penny had banded birds at my father's old stamping Ground of New Chum's Road, in the Brindabella Ranges (in the years after Dad had got too frail to keep going out on field trips).
We know many people in common.
Bronwyn, your point about colour is well made. Peter suggested that it might well appear as a danger signal to birds (which see very strongly in UV).